Gene therapy is becoming increasingly relevant for the treatment of prominent human diseases. Viral vectors are currently used in more than 50% of the gene therapy clinical trials, most of them aimed at cancer diseases. Clearly, the increasing needs of high-quality viral preparations required the elimination of process bottlenecks, streamlining the development of the viral into a real-world clinical tool . Virus production for clinical gene therapy can be a limiting step because many virus generation protocols rely on labor-intensive, bench-scale methods; robust, cost-effective strategies for the delivery of clinical-grade viruses are thus essential for the future of gene therapy. A comprehensive picture of key aspects on the integration of upstream and downstream processing is addressed in this chapter, by describing the case study of recombinant budded baculoviruses for gene therapy; scalable methods are described in detail as well as mandatory characterization techniques for a proper and complete quality assessment of the viral vectors.